The invention is referring to a method according to the preamble portion of claim 1.
It is known in connection with the laying of subsoil water cables first to lay the cable channel pipe and thereafter to introduce a thin auxiliary rope in order to draw the cable into and through the pipe by means of the auxiliary rope. If necessary a plurality of auxiliary ropes of increasing thickness and tensional strength can be drawn into the pipe one after the other. In order to reduce the buoyancy the pipe is filled with water immediately after being laid. It is also known to place an auxiliary rope in the cable channel pipe before the laying operation takes place.
In case of large continuous pipe lengths as for instance necessary for the passage of natural waters considerable forces are to be applied to in order to draw the auxiliary ropes or the cable through the pipe regardless the lubrication by the water in the pipe, in particular if a plurality of curves or radii are caused by the cross profile of a river bed. It has turned out that a nylon auxiliary rope of 5 mm thickness may be torn off in a pipe of a length of 3 km if a further rope or a cable is to be drawn into the pipe.
The object of the invention is to provide a method by which a rope-like or cable-like elongated element can be moved into a cable channel pipe filled with water in a more simple and operation-safe manner.